Quick and Dirty Class "AB" mod for KL300p

[Switch Kit]

Seems like these Italian amps have really gotten all the more popular over the last decade or so ? I realize this is a 11 year old thread (and a good one) Is this amp now a days still a class C amp ? or did they clean them up ? Thanks

 

[19wrc333]

Great thread thanks.

I've managed to grab the original images from the photobucket site. As that's a bit of manual work I figured to upload them here to hopefully save somebody some time. (The zip has them all numbered from 1 to 10)

.. and I've would have attached the images directly here too if they did not end up as .webp files, which they did. So a zip it is.

cheers,
Skyline

 

[doffo]

Great stuff here! I decided to do this mod on a little Silver Eagle 200 I got for working on a guys radio last week. It's a 2 X MRF455 class C box with no SSB delay. Since Eagle1911 has the rights to the "Quick and Dirty class AB Mod" I'll call mine the "White 'n' Nerdy class AB Mod"! Attached is a pic.

Once i got it all done, it works awesome, looks great on my O'scope, nice clean output. Does about 100W on low output, about 150W on high output, PEP. I did use a different resistor to the TIP42G transistor, as 220 ohms was keeping it "turned on", letting voltage go thru it at all times. I found that 1k ohms works perfect for switching the voltage.

Since this box did not have any SSB delay, I installed a 2200uF 35V capacitor across the relay coil. That gives me a nice delay for SSB, but isn't too long to interfere with AM should I want to use it for that mode.

Great thread, thanks to all that posted info and especially to Eagle1911 for the continued progress of the project!

~Cheers~

Do you recall where to put the 2200uF Capacitor? I am working on doing the same to a Comet 200 amp. In that same area in that picture, there is a 470uF 50v capacitor, but is that the one to change to a 2200uF? From what I understood the amp already worked in a sense that either one SSB and AM, the relays would stay on and not chatter away on SSB. Here is a picture underneath the amp.

And the top side.